Polishing assistant apparatus of polishing assistant system

ABSTRACT

A polishing assistant system applied to a polished wafer polished by a chemical mechanical polishing (CMP) is disclosed. The polishing assistant system includes a monitoring device for detecting a first polishing parameter of the polished wafer, and a polishing assistant apparatus. The polishing assistant apparatus further includes a platen for placing the polished wafer, a liquid supplier for supplying a slurry, a polishing controller for receiving the first polishing parameter and outputting a first control signal which is relative to a certain region of the polished wafer in response to the first polishing parameter, and a polish head electrically connected to the polishing controller and polishing the certain region of the polished wafer in response to the first control signal.

FIELD OF THE INVENTION

[0001] The present invention relates to a polishing assistant system, and more particularly to a polishing assistant system applied to a polished wafer which has been polished by a chemical mechanical polishing.

BACKGROUND OF THE INVENTION

[0002] Chemical mechanical polishing is a planarization technique to step by step remove the deposited layer on the wafer by a chemical reaction providing form the slurry and a mechanical polishing. Along the semiconductor production technology is developed from 0.25 μm into 0.175 μm level, the CMP is more and more important in the semiconductor procedure. However, the current CMP machine only includes a rotary polish unit and a clean unit to polish and clean the wafer.

[0003]FIG. 1 is a cutaway view illustrating a conventional polishing apparatus. A polish pad 10 is adhered on a platen 11 and used as a pad for a wafer 12 when polishing. A back side pressure 13 is applied to a carrier film 15, which is further controlling a removal rate and an uniformity of a polish head 14 to polish the wafer 12. However, the fuzz of the polish pad surface is deformed after long time polishing, so the polish pad 10 will loss the characteristic of absorbing the slurry. Thus, the removal rate of the wafer further decreases.

[0004]FIG. 2 is a plot illustrating a ratio of the maximum and the minimum of removal rate in a wafer surface along time according to the prior art. As shown in FIG. 2, along the using time of the polish pad (from the 25^(th) wafer to the 725^(th) wafer), the ratio of the maximum and the minimum of the removal rate for the wafer surface increases. That is, the removal rate non-uniformity also increases, and it is hard to achieve the planarization of the wafer.

[0005] Therefore, the purpose of the present invention is to develop a polishing assistant system to deal with the above situations encountered in the prior art.

SUMMARY OF THE INVENTION

[0006] It is therefore an object of the present invention to provide a polishing assistant system for compensating the removal rate non-uniformity resulted from the deformations of polish pad, carrier film, or relative consumables.

[0007] It is therefore another object of the present invention to provide a polishing assistant system for controlling the removal amount of every region of the wafer surface.

[0008] It is therefore an additional object of the present invention to provide a polishing assistant system for proceeding a fine polish process to achieve the planarization of the wafer.

[0009] According to an aspect of the present invention, there is provided a polishing assistant system applied to a polished wafer polished by a chemical mechanical polishing (CMP). The polishing assistant system includes a monitoring device for detecting a first polishing parameter of the polished wafer, and a polishing assistant apparatus. The polishing assistant apparatus further includes a platen for placing the polished wafer, a liquid supplier for supplying a slurry, a polishing controller for receiving the first polishing parameter and outputting a first control signal which is relative to a certain region of the polished wafer in response to the first polishing parameter, and a polish head electrically connected to the polishing controller and polishing the certain region of the polished wafer in response to the first control signal.

[0010] Preferably, the monitoring device further detects a second, a third, and a fourth polishing parameters. The second, third, and fourth polishing parameters are preferably a polish head down force, a polish head rotation speed, and a polishing time, respectively. In response to the second, third, and fourth polishing parameters, the polishing controller outputs a second, third, and fourth control signals, respectively, and the polish head polishes the certain region of the polished wafer in response to the second, third, and fourth control signals, respectively.

[0011] Preferably, the polishing controller includes a pressure controlling unit for controlling a pressure when the polish head polishing in response to the second polishing parameter, and a movable arm electrically connected to the pressure controlling unit and carrying the polish head to move to the certain region of the polished wafer in response to the first polishing parameter. The pressure controlling unit preferably has a control pressure ranged from 0.1 to 10 psi.

[0012] Preferably, the movable arm has an internal channel communicating between the pressure controlling unit and the polish head. The internal channel is preferably poured thereinto a medium and the control pressure is achieved by pressurizing the medium. For example, the medium is a liquid oil or a gas.

[0013] Preferably, the monitoring device further includes a detector for detecting a surface of the polished wafer to obtain a data, and a server electrically connected to the detector, obtaining the first polishing parameter according to the data, and transmitting the first polishing parameter to the polishing controller.

[0014] Preferably, the platen is a rotating platen. The rotating platen has preferably a rotation speed ranged from 1 to 50 revolutions per minute (rpm).

[0015] Preferably, the polish head is made of polyvinyl alcohol (PVA).

[0016] Preferably, the polish head is a rotatable polish head. The polish head preferably has a rotation speed ranged from 1 to 50 rpm.

[0017] Preferably, the polish head has a diameter ranged from 1 to 3 cm.

[0018] Preferably, the polishing assistant system further includes a polish head film disposed between the platen and the polished wafer for protecting the polished wafer.

[0019] According to an aspect of the present invention, there is provided a polishing assistant system applied to a polished wafer polished by a chemical mechanical polishing (CMP). The system includes a monitoring device for detecting a first polishing parameter of the polished wafer, and a polishing assistant apparatus. The polishing assistant apparatus further includes a platen for placing the polished wafer, a liquid supplier for supplying a slurry, and a polishing device polishing a certain region of the polished wafer in response to the first polishing parameter.

[0020] Preferably, the monitoring device further detects a second, a third, and a fourth polishing parameters, and the second, third, and fourth polishing parameters are a polish head down force, a polish head rotation speed, and a polishing time, respectively.

[0021] Preferably, the polishing device includes a polishing controller for receiving the first, second, third and fourth polishing parameters and outputting a first, second, third and fourth control signals in response to the first, second, third and fourth polishing parameters, respectively, and a polish head electrically connected to the polishing controller and polishing the certain region of the polished wafer in response to the first, second, third, and fourth control signals.

[0022] Preferably, the polishing controller includes a pressure controlling unit for controlling a pressure when the polish head is polishing in response to the second polishing parameter, and a movable arm electrically connected to the pressure controlling unit and carrying the polish head to move to the certain region of the polished wafer in response to the first polishing parameter.

[0023] The present invention may best be understood through the following description with reference to the accompanying drawings, in which:

BRIEF DESCRIPTION OF THE DRAWINGS

[0024]FIG. 1 is a cutaway view illustrating a conventional polishing apparatus;

[0025]FIG. 2 is a plot illustrating a ratio of the maximum and the minimum of removal rate in a wafer surface along time according to the prior art;

[0026]FIG. 3A is a diagram illustrating a preferred embodiment of a monitoring device in a polishing assistant system according to the present invention;

[0027]FIG. 3B is a diagram illustrating a preferred embodiment of a polishing assistant apparatus in a polishing assistant system according to the present invention;

[0028]FIG. 3C is a top view illustrating a movable arm path in the preferred embodiment of a polishing assistant system of FIG. 3B;

[0029]FIG. 4A is a plot illustrating an oxide thickness distribution on a surface of a polished wafer without treated by the polishing assistant system according to the present invention; and

[0030]FIG. 4B is a plot illustrating an oxide thickness distribution on a surface of a polished wafer with treated by the polishing assistant system according to the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0031] The present invention will now be described more specifically with reference to the following embodiments. It is to be noted that the following descriptions of preferred embodiments of this invention are presented herein for purpose of illustration and description only; it is not intended to be exhaustive or to be limited to the precise form disclosed.

[0032] The present invention provides a polishing assistant system applied to further fine polish a polished wafer which has been polished by a chemical mechanical polishing (CMP). The polishing assistant system includes a monitoring device and a polishing assistant apparatus. The monitoring device is used for detecting a surface of a polished wafer to obtain a first, second, third, and fourth polishing parameters which are a certain region of the polished wafer for fine polishing, i.e. a polish position, a polish head down force, a polish head rotation speed, and a polishing time, respectively. FIG. 3A is a diagram illustrating a preferred embodiment of a monitoring device in a polishing assistant system according to the present invention. The monitoring device further includes a detector 31 for detecting a surface of a polished wafer 30 to obtain a data, and a server 32 electrically connected to the detector 31, obtaining the first polishing parameter according to the data, and transmitting the first polishing parameter to the polishing assistant apparatus. In addition, the server 32 has a program, and the polishing parameters are obtained by applying the program to process the data.

[0033] As shown in FIG. 3B, the polishing assistant apparatus includes a platen 40, a liquid supplier 41, a polishing controller 422 and a polish head 421. The platen 40 is used for holding the polished wafer 30 and the liquid supplier 41 is used for supplying a slurry during polishing. In addition, the platen 40 is a rotating platen, so the polished wafer 30 will be carried to rotate in a rotation speed ranged from 1 to 50 revolutions per minute (rpm). Furthermore, a carrier film 43 disposed between the polished wafer 30 and the platen 40 is used for protecting the polished wafer 30.

[0034] The polishing controller 422 is used for receiving the first, second, third, and fourth polishing parameters transmitted from the server 32, outputting a first, second, third, and fourth control signals in response to the first, second, third, and fourth polishing parameters, respectively, and transmitting the first, second, third, and fourth control signals to the polish head 421 which is electrically connected to the polishing controller 422. The polish head 421 cooperated with the liquid supplier 41 proceeds a fine polish for a certain region of the polished wafer 30 in response to those polishing signals for improving the planarization of the surface of the polished wafer 30.

[0035] The polishing controller 422 further includes a pressure controlling unit 4221 and a movable arm 4222 electrically connected to the pressure controlling unit 4221. According to the second polishing parameter, the pressure controlling unit 4221 will control the polish head down force, ranged from 0.1 to 10 psi, when the polish head 421 polishes the polished wafer 30. Furthermore, the movable arm 4222 will move the polish head 421 to polish the certain regions of the polished wafer 30 in response to the first polishing parameter. FIG. 3C is a top view illustrating the movable arm path in FIG. 3B. As shown in FIG. 3C, the movable arm can move between A end and B end of the polished wafer 30.

[0036] In addition, the polish head down force is controlled by the pressure controlling unit 4221 through the following methods:

[0037] 1. The required pressure is directly imposed on the movable arm 4222 carrying into the polish head 421.

[0038] 2. The movable arm can have an internal channel 42221 communicating between the pressure controlling unit 4221 and the polish head 421. Thus, a liquid oil can be poured into the internal channel 42221 and the polish head down force can be indirectly controlled by directly imposing pressure on the liquid oil. Moreover, the liquid oil can be replaced by gas.

[0039] In addition, the polish head is a rotatable polish head having a rotation speed ranged from 1 to 50 rpm. The diameter range of the polish head is from 1 to 3 cm. The polish head is made of polyvinyl alcohol (PVA).

[0040]FIGS. 4A and 4B are plots illustrating an oxide thickness distribution on the surface of the polished wafer without and with treated by the polishing assistant system according to the present invention. Comparing FIG. 4A with FIG. 4B, the surface of the polished wafer treated by the polishing assistant system according to the present invention is more uniform than that without the treatment. Therefore, the present invention can improve the planarization of the wafer.

[0041] In sum, the polishing assistant system according to the present invention has the following advantages:

[0042] 1. The present invention can proceed a find polish onto the polished wafer to compensate the removal rate non-uniformity, which is resulted from the deformations of polish pad, carrier film, or relative consumables, causing to loss the planarization.

[0043] 2. The present invention can control the removal amount of every region on the wafer. Thus, it can solve the problems of over-removing in the partial surface of the wafer by the W-CMP, and the central-remaining in the surface of the wafer by the inter-layer dielectrics chemical mechanical polishing (ILD-CMP) or inter-metal dielectrics chemical mechanical polishing (IMD-CMP).

[0044] 3. The present invention also can solve the layer is non-uniformly formed on the wafer surface during the former process.

[0045] While the invention has been described in terms of what are presently considered to be the most practical and preferred embodiments, it is to be understood that the invention need not to be limited to the disclosed embodiment. On the contrary, it is intended to cover various modifications and similar arrangements included within the spirit and scope of the appended claims which are to be accorded with the broadest interpretation so as to encompass all such modifications and similar structures. 

What is claimed is:
 1. A polishing assistant system applied to a polished wafer polished by a chemical mechanical polishing (CMP), comprising: a monitoring device for detecting a first polishing parameter of said polished wafer; and a polishing assistant apparatus further comprising: a platen for placing said polished wafer; a liquid supplier for supplying a slurry; a polishing controller for receiving said first polishing parameter and outputting a first control signal which is relative to a certain region of said polished wafer in response to said first polishing parameter; and a polish head electrically connected to said polishing controller and polishing said certain region of said polished wafer in response to said first control signal.
 2. The polishing assistant system according to claim 1 wherein said monitoring device further detects a second, a third, and a fourth polishing parameters.
 3. The polishing assistant system according to claim 2 wherein said second, third, and fourth polishing parameters are a polish head down force, a polish head rotation speed, and a polishing time, respectively.
 4. The polishing assistant system according to claim 3 wherein in response to said second, third, and fourth polishing parameters, said polishing controller outputs a second, third, and fourth control signals, respectively, and said polish head polishes said certain region of said polished wafer in response to said second, third, and fourth control signals, respectively.
 5. The polishing assistant system according to claim 3 wherein said polishing controller comprises: a pressure controlling unit for controlling a pressure when said polish head polishing in response to said second polishing parameter; and a movable arm electrically connected to said pressure controlling unit and carrying said polish head to move to said certain region of said polished wafer in response to said first polishing parameter.
 6. The polishing assistant system according to claim 5 wherein said pressure controlling unit has a control pressure ranged from 0.1 to 10 psi.
 7. The polishing assistant system according to claim 5 wherein said movable arm has an internal channel communicating between said pressure controlling unit and said polish head.
 8. The polishing assistant system according to claim 7 wherein said internal channel is poured thereinto a medium and said control pressure is achieved by pressurizing said medium.
 9. The polishing assistant system according to claim 8 wherein said medium is one of a liquid oil and a gas. 10.The polishing assistant system according to claim 1 wherein said monitoring device further comprises: a detector for detecting a surface of said polished wafer to obtain a data; and a server electrically connected to said detector, obtaining said first polishing parameter according to said data, and transmitting said first polishing parameter to said polishing controller.
 11. The polishing assistant system according to claim 1 wherein said platen is a rotating platen.
 12. The polishing assistant system according to claim 1 wherein said rotating platen has a rotation speed ranged from 1 to 50 revolutions per minute (rpm).
 13. The polishing assistant system according to claim 1 wherein said polish head is made of polyvinyl alcohol (PVA).
 14. The polishing assistant system according to claim 1 wherein said polish head is a rotatable polish head.
 15. The polishing assistant system according to claim 14 wherein said polish head has a diameter ranged from 1 to 3 cm.
 16. The polishing assistant system according to claim 15 wherein said polish head has a rotation speed ranged from 1 to 50 rpm.
 17. The polishing assistant system according to claim 1 further comprising a polish head film disposed between said platen and said polished wafer for protecting said polished wafer.
 18. A polishing assistant system applied to a polished wafer polished by a chemical mechanical polishing (CMP), comprising: a monitoring device for detecting a first polishing parameter of said polished wafer; and a polishing assistant apparatus further comprising: a platen for placing said polished wafer; a liquid supplier for supplying a slurry; and a polishing device polishing a certain region of said polished wafer in response to said first polishing parameter.
 19. The polishing assistant system according to claim 18 wherein said monitoring device further detects a second, a third, and a fourth polishing parameters, and said second, third, and fourth polishing parameters are a polish head down force, a polish head rotation speed, and a polishing time, respectively.
 20. The polishing assistant system according to claim 19 wherein said polishing device comprises: a polishing controller for receiving said first, second, third and fourth polishing parameters and outputting a first, second, third and fourth control signals in response to said first, second, third and fourth polishing parameters, respectively; and a polish head electrically connected to said polishing controller and polishing said certain region of said polished wafer in response to said first, second, third, and fourth control signals.
 21. The polishing assistant system according to claim 20 wherein said polishing controller comprises: a pressure controlling unit for controlling a pressure when said polish head is polishing in response to said second polishing parameter; and a movable arm electrically connected to said pressure controlling unit and carrying said polish head to move to said certain region of said polished wafer in response to said first polishing parameter. 